When Donal MacIntyre's documentary A Very British Gangster was shown on Five last year, TV critics didn't bother to review it. How very wrong they were. Little did they know that the film is a masterpiece or, as they say in France, un chef d'oeuvre

MacIntyre's directorial debut has this year not only been nominated for a grand jury prize at Robert Redford's Sundance film festival, but also recently won the top prize at the Festival du film Policiers (the Detective film festival) in Cognac, France - an award previously given to such highly regarded film-makers as Larry Clark, Danny Boyle, Carl Franklin and Curtis Hanson.

And now, in the Paris Métro, there are posters for "un film de Donal MacIntyre", advertising the cinematic release of A Very British Gangster. In France, it seems, they talk about him in the same breath as Scorsese, and the hard-man investigative journalist has become an auteur - even if here he is known chiefly as the man who exposes putative bad men and has taken over the mantle of the human punchbag of documentary makers, Roger Cook.

The film follows three years in the life of Manchester gangster Dominic Noonan, who spent 22 of his 37 years in prison - and at the end of the film, returns to jail on firearms offences. Noonan, who gave MacIntyre total access to his life, is a captivating if repellent subject, a bull-necked Manc hoodlum, an openly gay, gobby gangster from Irish Catholic stock, a man who changed his name by deed poll to Lattlay Fottfoy, an acronym for the family motto: "Look after those that look after you, fuck off those that fuck off you."

So what is the 97-minute film's appeal? According to Libération's Bruno Icher: "No fiction in the world could succeed in putting such a shocking collection of sinister mugs on screen." The Hollywood Reporter's James Greenberg writes: "From his girth to his fondness for family, Manchester mob boss Dominic Noonan could be Tony Soprano's English cousin." Foreign critics compared Noonan to earlier British screen gangsters - Bob Hoskins in The Long Good Friday, Vinnie Jones in Lock, Stock and Two Smoking Barrels, though not Brian Conley in Circus.

Noonan started as a Hacienda bouncer who decided to fight back against gangs who muscled in to the club. He cut the head off a rival gangster's dog and placed it on the pool table of his pub, threatening to return later with a human head if the gang activity at the Hacienda carried on. The film traces the rest of his career: a biography of kidnappings, tortures, alleged murders, drug deals, arms possessions, jail time. It includes Noonan's claim, accompanied by a mirthlessly De Niro-like smile, to have gone straight.

"This is a gangster movie, first and foremost," says MacIntyre. "All the universal gangster themes are there - death, family, revenge, and innocence. There are murders, funerals, trials and acquittals, but in this instance all the actors, the set and the consequences are very real. It's a movie disguised as a documentary."

The doc, though, has its pretensions. There are ambitious crane shots over Manchester roofscapes and fanciful montages (thanks no doubt to editor Sally Hilton) as often as not to a song by Oasis. There's even a sequence in which Noonan and his crew walk down the street to the accompaniment of the George Baker Selection's Little Green Bag a la Reservoir Dogs.

"A Very British Gangster is a very watchable movie," writes Variety critic John Anderson, "one that explores an oft-exploited mob milieu and busts some of its fictional bubbles." Maybe. In Britain, though, MacIntyre is not an auteur yet.